Engineers need to analyze defects and other failures during micro-fabrication to troubleshoot, adjust, and improve micro-fabrication processes. For example, defect analysis is useful in all aspects of semiconductor production including design verification diagnostics, production diagnostics, as well as other aspects of microcircuit research and development. As device geometries continue to shrink and new materials are introduced, the structural complexity of today's semiconductors grows exponentially. Many of the structures created with these new materials are re-entrant, penetrating back through previous layers. Thus, the defects and structural causes of device failure are often hidden well below the surface.
Accordingly, defect analysis often requires cross-sectioning and viewing defects on a three-dimensional basis. With the growing use of copper conductor devices on semiconductor wafers, better systems capable of performing three dimensional defect analyses are more important than ever. This is because there are more defects that are buried and/or smaller, and in addition, chemical analysis is needed in many cases. Moreover, structural diagnostics solutions for defect characterization and failure analysis need to deliver more reliable results in less time, allowing designers and manufacturers to confidently analyze complex structural failures, understand the material composition, and source of defects, and increase yields.
Unfortunately, the defect characterization provided by conventional systems (e.g., optical inspection tools) is typically inadequate. The defect analysis process is typically slow and manual, with a technician individually deciding upon and performing each of the steps in the analysis. Rather than being integrated into the fabrication process, the defect analysis process is more laboratory-oriented than production oriented. In fact, in many fabrication facilities, defect analysis is performed in a laboratory located outside of the “clean room” environment. The results can take too long in being returned to the fab and the delay in analysis results can result in producing more defects or shutting down production. When a wafer is taken for detailed defect analysis, in many cases, the wafer must be discarded after it has been analyzed for fear of contamination and the like, even though only a small part of the wafer is destroyed by the analysis. With ever increasing wafer sizes and material process complexities, such losses can result in significant financial hardships.
Accordingly, what is needed is an improved defect analysis method and system.